A mechanism is provided in a storage device for performing a write operation. The mechanism configures a write buffer memory with a plurality of write buffer portions. Each write buffer portion is dedicated to a predetermined block size category within a plurality of block size categories. For each write operation from an initiator, the mechanism determines a block size category of the write operation. The mechanism performs each write operation by writing to a write buffer portion within the plurality of write buffer portions corresponding to the block size category of the write operation.